Autoregulatory control of microtubule binding in doublecortin-like kinase 1

Area of Science:

• Molecular biology
• Cell biology
• Biochemistry

Background:

• Doublecortin-like kinase 1 (DCLK1) is a microtubule-associated protein highly expressed in various cancers.
• DCLK1 is a therapeutic target for kinase inhibitors, but its physiological roles and regulation are not fully understood.

Purpose of the Study:

• To investigate the role of mammalian DCLK1 kinase activity in regulating microtubule binding.
• To elucidate the regulatory mechanism of DCLK1 activity.

Main Methods:

• Analysis of DCLK1 autophosphorylation.
• Site-directed mutagenesis to study the effects of C-terminal tail removal or residue mutation.
• Assessment of DCLK1's interaction with microtubules.

Main Results:

• DCLK1 autophosphorylates a C-terminal residue, restricting its kinase activity and preventing hyperphosphorylation in the microtubule-binding domain.
• Removal of the C-terminal tail or mutation of this residue increases phosphorylation in the doublecortin domains, abolishing microtubule binding.
• Autophosphorylation at specific sites within DCLK1 has opposing effects on its microtubule association.

Conclusions:

• DCLK1 autophosphorylation acts as a regulatory mechanism to tune its kinase activity and microtubule-binding affinity.
• These findings offer molecular insights into DCLK1's function in cancer and potential therapeutic strategies.